The supply of fuel to an internal combustion engine in a consistent and reliable manner is essential to proper vehicle operation. A typical vehicle fuel system includes a fuel pump which is submerged in a fuel tank. A fuel filter and a pressure regulator may be positioned on the respective intake and outlet sides of the fuel pump. Filtered fuel is thus delivered to a fuel rail, where it is ultimately injected into the engine cylinders. An Electronic Returnless Fuel System (ERFS) includes a sealed fuel tank and lacks a dedicated fuel return line. These and other features of the ERFS help to minimize vehicle emissions.
Conventional diagnostic techniques for a vehicle fuel system typically rely on knowledge of a prior failure condition. For example, when servicing the vehicle, a maintenance technician may determine by direct testing and/or review of a recorded diagnostic code that the fuel pump requires repair or replacement. This reactive diagnosis may not occur until vehicle performance has already been compromised. A proactive approach may be more advantageous, particularly when used with emerging vehicle designs utilizing an ERFS.